October 22, 2015

Shining More Light on Solar Panels

Thermal radiation readings on panels help Joshua Pearce and
his research team better understand ways to improve
low-concentration photovoltaic systems.

(October 22, 2015)  Solar panels are the beacon of renewable energy, yet they are not getting as much light as they could be. Joshua Pearce from Michigan Technological University and a team from Queen’s University in Canada have found a way to get more sun to shine on the panels and crank up the output by 30 percent or more. The work is published in the Institute of Electrical and Electronics Engineers (IEEE) Journal of Photovoltaics.

“We’re looking at this from a systems perspective,” Pearce says, who is an associate professor of materials science and engineering and electrical and computing engineering. He explains that the research focused on the system rather than individual panels mostly because the current set up for ground-mounted solar panel arrays is “wasting space.”

The iconic flat-faced solar panels installed in large-scale utility solar farms are spaced apart to prevent shading. As the sun shines on a photovoltaic system, sending electricity into the grid, a fair amount of that potential energy is lost as the light hits the ground between rows of panels. The solution is simple, says Pearce: Fill the space with a reflector to bounce sunlight back onto the panels.

Reflectors, or planar concentrators, are not widely used, however.

“Panels are usually warranted for 20 to 30 years,” Pearce says, explaining the warranty only guarantees under certain circumstances. “If you’re putting more sunlight on the panel with a reflector, you will have greater temperature swings and non-uniform illumination, but simple optics makes wrong predictions on the effect.”

Because of the uncertainty with potential hot spots, using reflectors currently voids warranties for solar farm operators. Pearce and his co-authors, found a way to predict the effects using bi-directional reflectance function, or BDRF.

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